Improvement in electro-magnetic burglar-alarms



W. B. GUERNSEY.

Burglar Alarm.

Patented Oct. 11, 1870.

lhvenior: a 5W7 wifnesa s 5km Ulvrrnn STATES PATENT OFFICE.

WILLIAM B. GUERNSEY, OF JERSEY CITY, NEW JERSEY.

IMPROVEMENT IN ELECTRO-MAGNETIC BURGLAR-ALARMS.

Specification forming part of Letters-Patent No. l0S,257, dated October '11, 1870.

- the open-circuit system. To this end I employ a continuous circuit, or a circuit capable of being made continuous at will, arranged with resistances, so that the current which is allowed to pass will not possesssufiicient electro-motive power to affect the alarm, but having such arrangements at windows or doors,

and other places to be guarded, as will on any' tampering there-with short-circuit the current past or around the said resistances to an extent sufiicient to actuate the alarm. v

Figure 1 shows in perspective two elect-ro- .:magnets with separate conductors connected with a common battery, each conductor passing through an alarm, and through suitable connection devices, which may be located in the frames of windows, or at any, desired points, in such a manner that the-opening of a door or window, or the performance ofany act which it is desired to detect, will connect one conductor with the other, and avoid both electro-magnets. For this purpose the magnet ofone conductor is located near thepositive pole, and that of the other near the negative pole of the battery. Fig. 2 illustrates a modification in which one magnet is dispensed with, and a simple resistance-coil is introduced in such a manner that the act to be detected will close a short circuit, avoiding the resistance, and thus sounding the alarm. This more simple form of the apparatus is applicable to places where a single window, door, or other object is to be protected.

P represents the positive, and N the nega: tive, pole of a battery, B. Of the full lines W, and the dot-ted lines W, each represents a continuousconductor passing through the alarm A through one or the other of the magnets M M, and one or other of the connectionsprings U G, which are arranged in pairs in the frames of the windows D in such a manner that the opening of either window will,

through the medium of the connecting-plates E, unite the two conductors.

It will be seen that there are two wire couductors, leading about the house or premises to be guarded, from the positive pole P of the battery shown to and through the hell or alarm, and thence returning to the negative pole N of the said battery. One of these conductors, W, indicated by a dotted line, leads direct from the battery to and through one of the resistance magnets M, entering at the binding-screw m and leaving from the hinding-screw m", and thence to each of .the four connecting-springs shown at C 000 at the two windows, theme from the last of said.

springs to the binding-screw a of the bell, and so through the bellmagnet, and out at the binding-screw a, and on to the other pole of the battery. But the other conductor W, marked with a heavy line in the drawing, leads to its connecting-springs G O" O C first, and then to and through its own resistance-magnet M. From this magnet the said conductor leads to and through the bell-mag; net to the battery in the same manner and direction as the other. I The severing of either of the said conductors would deprive one of the said resistance-magnets of its magnetism, consequently releasing its armature, and such release can easily, by known means, as by use of local battery, or of clock-worker other contrivances, be made to sound an alarm.

It will also be seen that the movement of either sash shown, to an extent. sufiicient to make contact between the two spring-connections in either frame by the metal strips E shown upon each sash, will, by allowing a current to pass through the bell-magnet unimpeded by the said resistances, cause the bell to ring. In other words, the bell-magnet having small resistance is not influenced by a current which has first been obliged to pass through a much greater resistance, but is readily influenced. by the short circuit when the resistances are eliminated.

Where but a single placeis tobeprotecte'das, for example, for the vault-door of a bankthe apparatus may be simplified by dispensing with one of the resistance-magnets, and employing instead a simple resistance, B, Fig. 2, so arranged thatthe opening of the door or window, or the doing of any act which the alarm is to detect, will short-circuit the couductor by forming a connection between the wires across or independently of the resistance.

Various other modifications will readily be suggested which will accomplish the object without departing from the essential principles of .the invention, the design being to obtain, an alarm in which the signals shall begiven or malicious, which may have happened to his instrument or its belongings.

I claim as my invention 1. The combination, in an electromagnetic alarm, of a continuous circuit or circuits with a sufficient resistanceor resistances, and an alarm or alarms when the said combination is so arranged that'thesevering or interrupting of said circuits, or, either of them, shall cause the said alarm or alarms to sound; and also that the short-circuiting or diverting the course of the electrical current in said circuit or circuits around or pastthe said resistance or resistances shall sound an alarm-411m, when the whole arrangement is properly combined with a sufficient battery, and with connections or. contrivances at points to be guarded, which will,

upon the doing of certain acts, or the happem ing of certain things, short-circuit the said electrical current or currents past or around the said resistance or resistances, and so give the'desired alarm. v

2. In a burglar or fire alarm, the combination of an open and a closed circuit, substantially as set forth.

W. B. GUERNSEY.

Witnesses:

Oeuvres KNIGHT, H. O. ELLIOTT. 

